One of every four deaths in the US is from cancer, making it the second leading cause of death, behind heart disease. According to an NIH estimate, this year about 555,500 Americans will die of cancer. Radioimmunotherapy (RIT) is one of the emerging modalities for the treatment of cancers. In RIT, a therapeutic dose of ionizing radiation is delivered to the cancer sites by attaching a suitable radionuclide to an antibody that binds to a specific antigen expressed by the cancer cells. The suitable nuclear emission properties (Ebeta = 1.7 MeV), the physical half-life (t1/2 = 17 hr), the decay-characteristics, and its availability from a generator, makes rhenium-188 one of the most attractive radionuclides for potential use in RIT. However, the complex labeling chemistry required for Re-188 and non-availability of a good chelating agent that forms stable complexes with Re-188 at high specific activities, limits the use of Re-188 in RIT. To overcome these problems, Lynntech is currently developing nanoparticle technology for a convenient labeling of cancer-targeting antibodies with Re-188 obtained from a readily available 188W/188 Re generator. During Phase I, the proof of concept will be demonstrated by labeling anti-CEA antibody with Re-188 using the new nanoparticle technology.